A) 6 min.to empty | B) 6 min.to fill |

C) 9 min.to empty | D) 9 min.to fill |

Explanation:

Clearly,pipe B is faster than pipe A and so,the tank will be emptied.

part to be emptied = 2/5

part emptied by (A+B) in 1 minute=

so, the tank will be emptied in 6 min

A) 360 lit | B) 480 lit |

C) 320 lit | D) 420 lit |

Explanation:

1/k - 1/20 = -1/24

k = 120

120 x 4 = 480

Therefore, the capacity of the cistern is 480 liters.

A) 85 min | B) 92 min |

C) 187 min | D) 144 min |

Explanation:

Let the slower pipe alone fill the tank in x min.

A) 24.315 minutes | B) 26.166 minutes |

C) 22.154 minutes | D) 24 minutes |

Explanation:

Upto first 5 minutes I, J and K will fill => 5[(1/20)+(1/30)+(1/40)] = 65/120

For next 6 minutes, J and K will fill => 6[(1/30)+(1/40)] = 42/120

So tank filled upto first 11 minutes = (65/120) + (42/120) = 107/120

So remaining tank = 13/120

Now at the moment filling with C and leakage @ 1/60 per minute= (1/40) - (1/70) = 3/280

So time taken to fill remaining 13/120 tank =(13/120) /(3/280) = 91/6 minutes

Hence total time taken to completely fill the tank = 5 + 6 + 91/6 = 26.16 minutes.

A) 3 minutes | B) 2 minutes |

C) 4 minutes | D) 5 minutes |

Explanation:

Let the total capacity of tank be 90 liters.

Capacity of tank filled in 1 minute by K = 3 liters.

Capacity of tank filled in 1 minute by L = 15 liters.

Therefore, capacity of the tank filled by both K and L in 1 minute = 18 liters.

Hence, time taken by both the pipes to overflow the tank = 90/18 = 5 minutes.

A) 48min | B) 72min |

C) 24min | D) None of these |

Explanation:

Given taps X and Y can fill the tank in 30 and 40 minutes respectively. Therefore,

part filled by tap X in 1 minute = 1/30

part filled by tap Y in 1 minute = 1/40

Tap Z can empty the tank in 60 minutes. Therefore,

part emptied by tap Z in 1 minute = 1/60

Net part filled by Pipes X,Y,Z together in 1 minute =

= 5/120 = 1/24

i.e., the tank can be filled in 24 minutes.